1. Field of the Invention
This invention relates to a photomicroscope using a still camera for recording microscope images.
2. Relevant Prior Art
The recording of microscope images using a still camera is possible with a photomicroscope. For example, German Patent 34 10 682 and U.S. Pat. No. 4,814,814 describe such photomicroscopes, in which a part of the photo beam path is mirrored onto several detectors, for example a diode array, for exposure metering with spatial resolution. The result of the exposure metering with spatial resolution is then used to determine and control the exposure time of the camera shutter. According to German Patent 34 10 682, the result of the exposure metering, especially of the image areas where the result of exposure metering is unsatisfactory and where insufficient light exposure of the film therefore has to be expected, can be displayed via a liquid-crystal display which can be inserted in the plane of an eyepiece reticle. According to U.S. Pat. No. 4,814,814, a similar result is obtained if the display unit is arranged not directly in the plane of the eyepiece reticle, but mirrored into this plane via a reflector arrangement.
With these photomicroscopes, the information obtained via the detectors is exclusively used for the determination of the correct exposure time of the still camera. It is intended neither to create a video image of the object by means of the detector signals nor to use the detector signals for microscope focusing. Apart from that, the sensitivity of the photo diodes or the diode array will not be sufficient for objects of very poor brightness.
The video microscope with video camera for the recording of a video image and a monitor for the visualization of the video image is know from U.S. Pat. No. 4,958,920. With this previously known video microscope, the video signals are also used for passive autofocusing based on the contrast of the video image. A passive autofocus system has, in fact, only a relatively small capture range, i.e., the object must already be relatively well focused in the first place to allow the autofocus to work. On the other hand, however, such a passive autofocus system features very precise focusing and its capture range is fully sufficient to compensate for the influence of minor object unevenness or the drift occurring in observation over a long period of time. Here, observation of the object is possible either via the eyepieces or via the monitor. However, an exposure of the microscope image using a still camera is not provided.
Furthermore, it is known, of course, that autofocus microscopes, e.g., according to U.S. Pat. No. 4,958,920 or the microscope offered by Applicant's assignee Carl Zeiss, under the name Axiotron AF described, for example, in Carl Zeiss' brochure marked CM-TS-II/87 Uoo, can be additionally equipped with a microscope camera, e.g., Carl Zeiss' "MC 100". In such instrument combinations, however, both the optical and the mechanical components of the autofocus system and the microscope camera are independent of each other. A separate detector for exposure metering is provided in the camera attachment.